﻿There is a usual way to formthe stiffness matrix, and that is int(Bt*D*B*|J|). If any helper have other types of K matrix calculation then it should:
- return true from method DoesOverrideKMatrixCalculation
- return 


Every element have a local coordination system which is rotated global coordination system (like local system for frame or triangle element).

Notes:
Transforming local stiffness matrix to global matrix with a lambda (3x3) matrix:

Kg = T1 * Kl * T2

T1 = t1  0   0  ...
	 0   T1  0  ...
	 0   0   T1 ...

T2 = T2  0   0  ...
	 0   T2  0  ...
	 0   0   T2 ...

Kl = k11 k12 k13 ...
	 k21 k22 k23 ...
	 k31 k32 k33 ...

Kg = t1 k11 t2		t1 k12 t2		t1 k13 t2   ...
	 t1 k21 t2		t1 k22 t2		t1 k23 t2   ...
	 t1 k31 t2		t1 k32 t2		t1 k33 t2   ...
	 
	 
stiffness at each node is 6x6 but t1 and t2 are 3x3, so kij is 3x3 matrix starting from Dx dof or Rx dof

High performance Integration of Bt*D*B*det(j) for stiffness
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